What looked only two weeks ago like a mild winter for deer in northern Minnesota has quickly turned into a season of growing concern on the part of wildlife managers and deer hunters.
"It's shaping up to be a really tough winter,'' said Bob Wright, a wildlife biologist and computer mapping expert who maintains a special winter severity index for the Department of Natural Resources.
His most recent report on Feb. 6 shaded the Arrowhead Region in northeastern Minnesota with values under 80 on a scale that equates a mild winter with any number under 100 at the end of the season. Season-ending scores of more than 180 indicate harsh severity.
But the scores Up North are rising quickly, with recent snowfalls pushing the Arrowhead's snowpack beyond 2 feet in depth with areas along the North Shore approaching or surpassing depths of 40 inches. Even at 15 inches of snow, deer movements are hampered.
Wright said Tuesday he will now accelerate his work to produce weekly severity reports for white-tailed deer throughout the state. He has started to receive calls of concern from DNR wildlife offices in the state's northern counties.
"We're changing really fast,'' said Tom Rusch, DNR area wildlife manager in Tower, Minn. "It just won't stop snowing.''
Rusch said deer in his region have been dealing with deep snow for the past month and their mobility is decreasing.
"We're into a real winter,'' he said.
Scores on the winter severity index have already topped 100 in central Cook County in the heart of Minnesota's moose range. And the points are adding up quickly. If the snow and cold linger into April like last year, Rusch said, northern herds of deer could suffer weather-related mortality from predators or from withering body condition.
A severe end to the winter also would hurt 2019 fawn production, he said.
"They are running out of groceries … it gets tougher for them to get around,'' Rusch said.
But he also said a sustained thaw in March could change everything. Deer will be looking for fresh browsing vegetation and the forage could start to appear early on roadsides and south-facing slopes. But getting to that all-important green-up in a timely manner will require a change in the weather pattern, he said. It takes a long time to melt 30 inches of snow in the North Woods.
"From what I see out the window right now we are heading for a real difficult winter lacking some kind of reprieve,'' Rusch said.
In the Grand Rapids area, Craig Engwall of the Minnesota Deer Hunters Association (MDHA), said he's starting to see deer struggle to move around.
"Not too long ago I thought it was going to be a wimpy winter,'' Engwall said. "Since January first it has come on in a fury.''
His hope is that deer will be better suited to withstand the back end of winter because conditions were mild until January set in.
The last severe winter for deer in Minnesota was 2013-14. The season ended with index values consistently higher than 180 east of a diagonal line from Warroad to Hinckley. The desperate conditions for deer prompted large-scale feedings by MDHA against the advice of DNR wildlife biologists.
Barbara Keller, DNR's new big game program supervisor, said feeding struggling deer on a large scale is still considered a bad idea. The sites draw the animals too close together, raising the risk of disease outbreaks. In addition, severe winters bring about changes in the guts of deer, preventing them from digesting food that is suddenly on a higher nutritional plane. In some cases, the shock can kill them.
Keller also said heavy concentrations of deer at feeding sites triggers aggressive behavior in some animals, adding to stress levels in the herd. Concentrated deer feeding also can invite conflict between deer and landowners, she said.
